U.S. patent application number 17/318668 was filed with the patent office on 2021-08-26 for timing adjustments with mixed numerologies.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Sony Akkarakaran, Amir Aminzadeh Gohari, Peter Pui Lok Ang, Peter Gaal, Muhammad Nazmul Islam, Tao Luo.
Application Number | 20210266855 17/318668 |
Document ID | / |
Family ID | 1000005582925 |
Filed Date | 2021-08-26 |
United States Patent
Application |
20210266855 |
Kind Code |
A1 |
Akkarakaran; Sony ; et
al. |
August 26, 2021 |
TIMING ADJUSTMENTS WITH MIXED NUMEROLOGIES
Abstract
Certain aspects of the present disclosure relate to
communication systems, and more particularly, to interpreting a
timing advance (TA) command for members of a timing advance group
(TAG), such as different uplink component carriers and/or different
bandwidth parts, having different numerologies, such as different
subarrier spacing (SCS). A method that may be performed by a user
equipment (UE) includes receiving, from a base station (BS), a TA
command. The UE interprets the TA command differently for different
members of a same TAG, associated with different numerologies. The
UE applies a timing adjustment when transmitting an uplink
transmission to the BS based, at least in part, on the
interpretation.
Inventors: |
Akkarakaran; Sony; (Poway,
CA) ; Gaal; Peter; (San Diego, CA) ; Islam;
Muhammad Nazmul; (Littleton, MA) ; Aminzadeh Gohari;
Amir; (Sunnyvale, CA) ; Ang; Peter Pui Lok;
(San Diego, CA) ; Luo; Tao; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005582925 |
Appl. No.: |
17/318668 |
Filed: |
May 12, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16284045 |
Feb 25, 2019 |
11019590 |
|
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17318668 |
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62654182 |
Apr 6, 2018 |
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62636026 |
Feb 27, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/001 20130101;
H04L 27/2607 20130101; H04W 56/0015 20130101; H04W 72/0446
20130101; H04L 5/0094 20130101; H04W 56/0045 20130101 |
International
Class: |
H04W 56/00 20060101
H04W056/00; H04L 5/00 20060101 H04L005/00; H04L 27/26 20060101
H04L027/26; H04W 72/04 20060101 H04W072/04 |
Claims
1. A method for wireless communications by a user equipment (UE),
comprising: receiving, from a base station (BS), a timing advance
(TA) command; rounding the TA command to a TA granularity for a
member of a timing advance group (TAG), wherein the TA granularity
of the TA command is associated with a subcarrier spacing (SCS) and
members of the TAG associated with different numerologies comprise
one or more members associated with different SCSs and wherein
rounding the TA command to TA granularity comprises rounding the TA
command based on an SCS associated with the member of the TAG; and
applying a timing adjustment when transmitting an uplink
transmission to the BS based, at least in part, on the rounded TA
command.
2. The method of claim 1, wherein the SCS is the largest SCS in the
TAG.
3. The method of claim 1, wherein the members of the TAG comprise
one or more component carriers or one or more bandwidth parts.
4. The method of claim 1, wherein applying the timing adjustment
comprises applying the TA command differently based on an SCS
associated with each member of the TAG.
5. The method of claim 1, wherein: a SCS of a first member of the
TAG is not an integer multiple of the SCS of the TA granularity,
and rounding the TA command-comprises rounding the TA command to a
granularity applied to the first member.
6. The method of claim 5, wherein rounding the TA command
comprises: determining a TA based on an indicated largest SCS of
the TAG, and rounding the first TA to a second TA.
7. The method of claim 5, wherein rounding the TA command comprises
one or more of: rounding the TA command down to a nearest supported
granularity, rounding the TA command up to a nearest supported
granularity, or randomly rounding the TA command up or down to a
nearest supported granularity.
8. The method of claim 7, wherein rounding the TA command to a
granularity comprises determining the rounding of the TA command up
or down to a nearest supported granularity based on a deterministic
pattern of multiple received TA commands.
9. The method of claim 1, wherein: an SCS of a first member of the
TAG is not an integer multiple of the SCS of the TA granularity,
and rounding the TA command to the TA granularity comprises
rounding a granularity applied to the first member to a nominal
coarse TA granularity larger than the TA granularity.
10. The method of claim 9, further comprising tracking a difference
between the TA granularity associated with the SCS and the nominal
coarse TA granularity applied to the first member of the TAG.
11. The method of claim 10, further comprising applying the
difference to a future TA command.
12. The method of claim 10, further comprising: determining a
change in downlink timing at the UE; and autonomously applying the
difference based, at least in part on the determination, to UL
transmission to the BS.
13. The method of claim 10, further comprising resetting the
difference based on at least one of: a reconfiguration of members
of the TAG, a change in the SCS, a received command from the BS, or
expiry of a TA-timer.
14. The method of claim 1, wherein: an SCS of a second member of
the TAG is an integer multiple of the SCS of the TA granularity;
and applying the timing adjustment comprises applying the TA
granularity to the second member.
15. The method of claim 1, wherein the members of the TAG
associated with different numerologies comprise at least one of:
component carriers (CCs) or bandwidth parts (BWPs) having different
SCS.
16. An apparatus for wireless communications, comprising: means for
receiving, from another apparatus, a timing advance (TA) command;
means for rounding the TA command to a TA granularity for a member
of a timing advance group (TAG), wherein the TA granularity of the
TA command is associated with a subcarrier spacing (SCS) and
members of the TAG associated with different numerologies comprise
one or more members associated with different SCSs and wherein
rounding the TA command to TA granularity comprises rounding the TA
command based on an SCS associated with the member of the TAG; and
means for applying a timing adjustment when transmitting an uplink
transmission to the another apparatus based, at least in part, on
the rounded TA command.
17. The apparatus of claim 16, wherein the SCS is the largest SCS
in the TAG.
18. The apparatus of claim 16, wherein the members of the TAG
comprise one or more component carriers or one or more bandwidth
parts.
19. The apparatus of claim 16, wherein applying the timing
adjustment comprises applying the TA command differently based on
an SCS associated with each member of the TAG.
20. The apparatus of claim 16, wherein: a SCS of a first member of
the TAG is not an integer multiple of the SCS of the TA
granularity, and rounding the TA command to the TA granularity
comprises rounding the TA command to a granularity applied to the
first member.
21. The apparatus of claim 20, wherein rounding the TA command
comprises: determining a TA based on an indicated largest SCS of
the TAG, and rounding the first TA to a second TA.
22. The apparatus of claim 20, wherein rounding the TA command
comprises one or more of: rounding the TA command down to a nearest
supported granularity, rounding the TA command up to a nearest
supported granularity, or randomly rounding the TA command up or
down to a nearest supported granularity.
23. The apparatus of claim 16, wherein: an SCS of a first member of
the TAG is not an integer multiple of the SCS of the TA
granularity, and rounding the TA command to the TA granularity
comprises rounding a granularity applied to the first member to a
nominal coarse TA granularity larger than the TA granularity of the
TA command.
24. The apparatus of claim 23, further comprising tracking a
difference between the TA granularity associated with the SCS and
the nominal coarse TA granularity applied to the first member of
the TAG.
25. The apparatus of claim 24, further comprising means for
applying the difference to a future TA command.
26. The apparatus of claim 16, wherein: an SCS of a second member
of the TAG is an integer multiple of the SCS of the TA granularity;
and applying the timing adjustment comprises applying the TA
granularity to the second member.
27. An apparatus for wireless communications, comprising: a
receiver configured to receive, from another apparatus, a timing
advance (TA) command; at least one processor coupled with a memory
and configured to: round the TA command to a TA granularity for a
member of a timing advance group (TAG), wherein the TA granularity
of the TA command is associated with a subcarrier spacing (SCS) and
members of the TAG associated with different numerologies comprise
one or more members associated with different SCSs and wherein
rounding the TA command to TA granularity comprises rounding the TA
command based on an SCS associated with the member of the TAG; and
apply a timing adjustment when transmitting an uplink transmission
to the another apparatus based, at least in part, on the rounded TA
command.
28. A computer readable non-transitory medium having computer
executable code stored thereon for wireless communications,
comprising: code for receiving, from an apparatus, a timing advance
(TA) command; code for rounding the TA command to a TA granularity
for a member of a timing advance group (TAG), wherein the TA
granularity of the TA command is associated with a subcarrier
spacing (SCS) and members of the TAG associated with different
numerologies comprise one or more members associated with different
SCSs and wherein rounding the TA command to TA granularity
comprises rounding the TA command based on an SCS associated with
the member of the TAG; and code for applying a timing adjustment
when transmitting an uplink transmission to the apparatus based, at
least in part, on the rounded TA command.
Description
CLAIM OF PRIORITY
[0001] This application claims benefit of and priority to U.S.
Provisional Patent Application Ser. No. 62/636,026, filed Feb. 27,
2018; U.S. Provisional Patent Application Ser. No. 62/654,182,
filed Apr. 6, 2018; and to U.S. Non-Provisional patent application
Ser. No. 16/284,045, filed Feb. 25, 2019, the entire contents of
which are herein incorporated by reference in their entireties as
if fully set forth below and for all applicable purposes.
FIELD OF THE DISCLOSURE
[0002] Aspects of the present disclosure relate to wireless
communications, and more particularly, to techniques for timing
advance (TA) commands for uplink communications with mixed
numerologies.
DESCRIPTION OF RELATED ART
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, broadcasts, etc. These wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power, etc.).
Examples of such multiple-access systems include 3rd Generation
Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE
Advanced (LTE-A) systems, code division multiple access (CDMA)
systems, time division multiple access (TDMA) systems, frequency
division multiple access (FDMA) systems, orthogonal frequency
division multiple access (OFDMA) systems, single-carrier frequency
division multiple access (SC-FDMA) systems, and time division
synchronous code division multiple access (TD-SCDMA) systems, to
name a few.
[0004] In some examples, a wireless multiple-access communication
system may include a number of base stations (BSs), which are each
capable of simultaneously supporting communication for multiple
communication devices, otherwise known as user equipments (UEs). In
an LTE or LTE-A network, a set of one or more base stations may
define an eNodeB (eNB). In other examples (e.g., in a next
generation, a new radio (NR), or 5G network), a wireless multiple
access communication system may include a number of distributed
units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads
(RHs), smart radio heads (SRHs), transmission reception points
(TRPs), etc.) in communication with a number of central units (CUs)
(e.g., central nodes (CNs), access node controllers (ANCs), etc.),
where a set of one or more DUs, in communication with a CU, may
define an access node (e.g., which may be referred to as a BS, 5G
NB, next generation NodeB (gNB or gNodeB), transmission reception
point (TRP), etc.). A BS or DU may communicate with a set of UEs on
downlink channels (e.g., for transmissions from a BS or DU to a UE)
and uplink channels (e.g., for transmissions from a UE to BS or
DU).
[0005] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. NR (e.g., new
radio or 5G) is an example of an emerging telecommunication
standard. NR is a set of enhancements to the LTE mobile standard
promulgated by 3GPP. NR is designed to better support mobile
broadband Internet access by improving spectral efficiency,
lowering costs, improving services, making use of new spectrum, and
better integrating with other open standards using OFDMA with a
cyclic prefix (CP) on the downlink (DL) and on the uplink (UL). To
these ends, NR supports beamforming, multiple-input multiple-output
(MIMO) antenna technology, and carrier aggregation.
[0006] However, as the demand for mobile broadband access continues
to increase, there exists a need for further improvements in NR and
LTE technology. Preferably, these improvements should be applicable
to other multi-access technologies and the telecommunication
standards that employ these technologies.
SUMMARY
[0007] The systems, methods, and devices of the disclosure each
have several aspects, no single one of which is solely responsible
for its desirable attributes. Without limiting the scope of this
disclosure as expressed by the claims which follow, some features
will now be discussed briefly. After considering this discussion,
and particularly after reading the section entitled "Detailed
Description" one will understand how the features of this
disclosure provide advantages that include improved communications
between access points and stations in a wireless network.
[0008] Certain aspects provide a method for wireless communication
by a user equipment (UE). The method generally includes receiving,
from a base station (BS), a timing advance (TA) command. The method
generally includes interpreting the TA command differently for
different members of a same timing advance group (TAG). The members
of the TAG are associated with different numerologies. The method
generally includes applying a timing adjustment when transmitting
an uplink transmission to the BS based, at least in part, on the
interpretation.
[0009] Certain aspects provide an apparatus for wireless
communication. The apparatus generally includes means for
receiving, from another apparatus, a TA command. The apparatus
generally includes means for interpreting the TA command
differently for different members of a same TAG. The members of the
TAG are associated with different numerologies. The apparatus
generally includes means for applying a timing adjustment when
transmitting an uplink transmission to the other apparatus based,
at least in part, on the interpretation.
[0010] Certain aspects provide an apparatus for wireless
communication. The apparatus generally includes a receiver
configured to receive, from another apparatus, a TA command. The
apparatus generally includes at least one processor coupled with a
memory and configured to interpret the TA command differently for
different members of a same TAG. The members of the TAG are
associated with different numerologies. The apparatus generally
includes a transmitter configured to apply a timing adjustment when
transmitting an uplink transmission to the other apparatus based,
at least in part, on the interpretation.
[0011] Certain aspects provide a computer readable medium having
computer executable code stored thereon for wireless communication.
The computer readable medium generally includes code for receiving,
from a BS, a TA command. The computer readable medium generally
includes code for interpreting the TA command differently for
different members of a same TAG. The members of the TAG are
associated with different numerologies. The computer readable
medium generally includes code for applying a timing adjustment
when transmitting an uplink transmission to the BS based, at least
in part, on the interpretation.
[0012] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the appended drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] So that the manner in which the above-recited features of
the present disclosure can be understood in detail, a more
particular description, briefly summarized above, may be had by
reference to aspects, some of which are illustrated in the
drawings. It is to be noted, however, that the appended drawings
illustrate only certain typical aspects of this disclosure and are
therefore not to be considered limiting of its scope, for the
description may admit to other equally effective aspects.
[0014] FIG. 1 is a block diagram conceptually illustrating an
example telecommunications system, in accordance with certain
aspects of the present disclosure.
[0015] FIG. 2 is a block diagram illustrating an example logical
architecture of a distributed radio access network (RAN), in
accordance with certain aspects of the present disclosure.
[0016] FIG. 3 is a diagram illustrating an example physical
architecture of a distributed RAN, in accordance with certain
aspects of the present disclosure.
[0017] FIG. 4 is a block diagram conceptually illustrating a design
of an example base station (BS) and user equipment (UE), in
accordance with certain aspects of the present disclosure.
[0018] FIG. 5 is a diagram showing examples for implementing a
communication protocol stack, in accordance with certain aspects of
the present disclosure.
[0019] FIG. 6 illustrates an example of a frame format for a new
radio (NR) system, in accordance with certain aspects of the
present disclosure.
[0020] FIG. 7 illustrates an example scenario with supplemental
uplink (SUL) component carriers, in accordance with certain aspects
of the present disclosure.
[0021] FIG. 8 is a table showing example timing advance (TA) units
for different subcarrier spacing, in accordance with certain
aspects of the present disclosure.
[0022] FIG. 9 is a flow diagram illustrating example operations for
wireless communications by a UE, in accordance with certain aspects
of the present disclosure.
[0023] FIG. 10 illustrates a communications device that may include
various components configured to perform operations for the
techniques disclosed herein in accordance with aspects of the
present disclosure.
[0024] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one aspect may be beneficially utilized on other
aspects without specific recitation.
DETAILED DESCRIPTION
[0025] Aspects of the present disclosure provide apparatus,
methods, processing systems, and computer readable mediums for
timing adjustment with mixed numerologies.
[0026] In certain systems (e.g., 5G NR systems), timing advance
(TA) commands are issued by a base station (BS) to the user
equipment (UE). The TA commands may be determined in an effort to
ensure that uplink transmissions from the UE(s) arrive at the BS
synchronously and are orthogonal to each other. In some examples,
an UL transmission from a UE located close to the BS may have a
shorter round trip time (RTT) as compared to a UE located farther
away from the BS. The TA commands may be determined in an effort to
enable to the BS to receive and process UL signaling using a single
fast Fourier transform (FFT) window.
[0027] As a UE moves further away from the BS, the RTT increases.
Thus, the TA commands from the BS may not ensure synchronization.
In absence of adjustments by the UE, the time at which UL
transmissions from the UE arrive at the BS may start to lag behind
other UEs that are located closer to the BS. To compensate for the
difference in RTT, the BS sends the TA command to adjust the UE's
timing.
[0028] In certain systems, such certain long term evolution (LTE)
systems, the TAs are of a fixed granularity that is a function of
the LTE subcarrier spacing (e.g., 15 kHz). As LTE supports a single
SCS, the fixed granularity may be thought of as a constant. Other
wireless communication systems, such as 5G NR systems, support
mixed numerologies for UL transmissions. As described herein,
numerology refers to a set of parameters that define a structure of
time and frequency resources used for communication. Such
parameters may include, for example, the subcarrier spacing, type
of cyclic prefix (e.g., such as normal CP or extended CP), and
transmission time intervals (TTIs) (e.g., such as subframe or slot
durations). A single TA command may apply to an entire timing
adjustment group (TAG); however, members of the TAG may be
associated with a different numerologies. Accordingly, UEs may not
be able to apply a same TA granularity to all UL transmissions.
[0029] Aspects of the present disclosure provide techniques and
apparatus for determining TA granularity (e.g., for a received TA
command) among uplink carriers that have mixed (e.g., different) UL
numerologies. As discussed above, 5G NR, for example, may support
mixed numerologies across cells with carrier aggregation and across
bandwidth parts (BWPs), or subbands, within a cell. Using aspects
presented herein, the UE may determine the TA to use for UL
transmission, based in part on the numerology associated with one
or more of the uplink carriers and/or numerology associated with
one or more supported uplink bandwidth parts.
[0030] In some examples, in accordance with aspects described
herein, a UE receives a TA command, interprets the TA command based
on a numerology associated with an UL transmission, and applies a
timing adjustment when transmitting UL signaling to the BS based,
at least in part, on the interpreted TA. The same TA command may
have a different impact on different members of a TAG.
Advantageously, this allows UL signaling having mixed numerology
system to arrive at a BS in a synchronous (e.g., time-aligned)
manner through application of a same TA command.
[0031] The following description provides examples, and is not
limiting of the scope, applicability, or examples set forth in the
claims. Changes may be made in the function and arrangement of
elements discussed without departing from the scope of the
disclosure. Various examples may omit, substitute, or add various
procedures or components as appropriate. For instance, the methods
described may be performed in an order different from that
described, and various steps may be added, omitted, or combined.
Also, features described with respect to some examples may be
combined in some other examples. For example, an apparatus may be
implemented or a method may be practiced using any number of the
aspects set forth herein. In addition, the scope of the disclosure
is intended to cover such an apparatus or method which is practiced
using other structure, functionality, or structure and
functionality in addition to, or other than, the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim. The word "exemplary" is used herein to
mean "serving as an example, instance, or illustration." Any aspect
described herein as "exemplary" is not necessarily to be construed
as preferred or advantageous over other aspects.
[0032] The techniques described herein may be used for various
wireless communication technologies, such as LTE, CDMA, TDMA, FDMA,
OFDMA, SC-FDMA and other networks. The terms "network" and "system"
are often used interchangeably. A CDMA network may implement a
radio technology such as Universal Terrestrial Radio Access (UTRA),
cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other
variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856
standards. A TDMA network may implement a radio technology such as
Global System for Mobile Communications (GSM). An OFDMA network may
implement a radio technology such as NR (e.g. 5G RA), Evolved UTRA
(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunication System (UMTS).
[0033] New Radio (NR) is an emerging wireless communications
technology under development in conjunction with the 5G Technology
Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE-Advanced
(LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS,
LTE, LTE-A and GSM are described in documents from an organization
named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB
are described in documents from an organization named "3rd
Generation Partnership Project 2" (3GPP2). The techniques described
herein may be used for the wireless networks and radio technologies
mentioned above as well as other wireless networks and radio
technologies. For clarity, while aspects may be described herein
using terminology commonly associated with 3G and/or 4G wireless
technologies, aspects of the present disclosure can be applied in
other generation-based communication systems, such as 5G and later,
including NR technologies.
Example Wireless Communications System
[0034] FIG. 1 illustrates an example wireless communication network
100 in which aspects of the present disclosure may be performed.
For example, the wireless communication network 100 may be a New
Radio (NR) or 5G network. A UE 120 in the wireless communication
network 100 may receive a timing advance (TA) command from a BS 110
in the wireless communication network 100. The UE 120 may interpret
the TA command based on a numerology associated with an uplink
transmission (or associated with the UE). For example, as shown in
FIG. 1, the UE 120a has a TA command determination module
configured to interpret the TA command, in accordance with certain
aspects of the present disclosure. The UE 120 may apply a timing
adjustment when transmitting uplink signaling to the BS 110. The
timing adjustment applied by the UE 120 may be based, at least in
part, on the interpreted TA. The same TA command may have a
different impact on (and may be interpreted differently by)
different members of a timing advance group (TAG).
[0035] As illustrated in FIG. 1, the wireless communication network
100 may include a number of base stations (BSs) 110 and other
network entities. A BS may be a station that communicates with user
equipments (UEs). Each BS 110 may provide communication coverage
for a particular geographic area. In 3GPP, the term "cell" can
refer to a coverage area of a Node B (NB) and/or a NB subsystem
serving this coverage area, depending on the context in which the
term is used. In NR systems, the term "cell" and next generation
NodeB (gNB or gNodeB), NR BS, 5G NB, access point (AP), or
transmission reception point (TRP) may be interchangeable. In some
examples, a cell may not necessarily be stationary, and the
geographic area of the cell may move according to the location of a
mobile BS. In some examples, the base stations may be
interconnected to one another and/or to one or more other base
stations or network nodes (not shown) in wireless communication
network 100 through various types of backhaul interfaces, such as a
direct physical connection, a wireless connection, a virtual
network, or the like using any suitable transport network.
[0036] In general, any number of wireless networks may be deployed
in a given geographic area. Each wireless network may support a
particular radio access technology (RAT) and may operate on one or
more frequencies. A RAT may also be referred to as a radio
technology, an air interface, etc. A frequency may also be referred
to as a carrier, a subcarrier, a frequency channel, a tone, a
subband, etc. Each frequency may support a single RAT in a given
geographic area in order to avoid interference between wireless
networks of different RATs. In some cases, NR or 5G RAT networks
may be deployed.
[0037] A BS may provide communication coverage for a macro cell, a
pico cell, a femto cell, and/or other types of cells. A macro cell
may cover a relatively large geographic area (e.g., several
kilometers in radius) and may allow unrestricted access by UEs with
service subscription. A pico cell may cover a relatively small
geographic area and may allow unrestricted access by UEs with
service subscription. A femto cell may cover a relatively small
geographic area (e.g., a home) and may allow restricted access by
UEs having an association with the femto cell (e.g., UEs in a
Closed Subscriber Group (CSG), UEs for users in the home, etc.). A
BS for a macro cell may be referred to as a macro BS. A BS for a
pico cell may be referred to as a pico BS. A BS for a femto cell
may be referred to as a femto BS or a home BS. In the example shown
in FIG. 1, the BSs 110a, 110b and 110c may be macro BSs for the
macro cells 102a, 102b and 102c, respectively. The BS 110x may be a
pico BS for a pico cell 102x. The BSs 110y and 110z may be femto
BSs for the femto cells 102y and 102z, respectively. A BS may
support one or multiple (e.g., three) cells.
[0038] Wireless communication network 100 may also include relay
stations. A relay station is a station that receives a transmission
of data and/or other information from an upstream station (e.g., a
BS or a UE) and sends a transmission of the data and/or other
information to a downstream station (e.g., a UE or a BS). A relay
station may also be a UE that relays transmissions for other UEs.
In the example shown in FIG. 1, a relay station 110r may
communicate with the BS 110a and a UE 120r in order to facilitate
communication between the BS 110a and the UE 120r. A relay station
may also be referred to as a relay BS, a relay, etc.
[0039] Wireless communication network 100 may be a heterogeneous
network that includes BSs of different types, e.g., macro BS, pico
BS, femto BS, relays, etc. These different types of BSs may have
different transmit power levels, different coverage areas, and
different impact on interference in the wireless communication
network 100. For example, macro BS may have a high transmit power
level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may
have a lower transmit power level (e.g., 1 Watt).
[0040] Wireless communication network 100 may support synchronous
or asynchronous operation. For synchronous operation, the BSs may
have similar frame timing, and transmissions from different BSs may
be approximately aligned in time. For asynchronous operation, the
BSs may have different frame timing, and transmissions from
different BSs may not be aligned in time. The techniques described
herein may be used for both synchronous and asynchronous
operation.
[0041] A network controller 130 may couple to a set of BSs and
provide coordination and control for these BSs. The network
controller 130 may communicate with the BSs 110 via a backhaul. The
BSs 110 may also communicate with one another (e.g., directly or
indirectly) via wireless or wireline backhaul.
[0042] The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed
throughout the wireless communication network 100, and each UE may
be stationary or mobile. A UE may also be referred to as a mobile
station, a terminal, an access terminal, a subscriber unit, a
station, a Customer Premises Equipment (CPE), a cellular phone, a
smart phone, a personal digital assistant (PDA), a wireless modem,
a wireless communication device, a handheld device, a laptop
computer, a cordless phone, a wireless local loop (WLL) station, a
tablet computer, a camera, a gaming device, a netbook, a smartbook,
an ultrabook, an appliance, a medical device or medical equipment,
a biometric sensor/device, a wearable device such as a smart watch,
smart clothing, smart glasses, a smart wrist band, smart jewelry
(e.g., a smart ring, a smart bracelet, etc.), an entertainment
device (e.g., a music device, a video device, a satellite radio,
etc.), a vehicular component or sensor, a smart meter/sensor,
industrial manufacturing equipment, a global positioning system
device, or any other suitable device that is configured to
communicate via a wireless or wired medium. Some UEs may be
considered machine-type communication (MTC) devices or evolved MTC
(eMTC) devices. MTC and eMTC UEs include, for example, robots,
drones, remote devices, sensors, meters, monitors, location tags,
etc., that may communicate with a BS, another device (e.g., remote
device), or some other entity. A wireless node may provide, for
example, connectivity for or to a network (e.g., a wide area
network such as Internet or a cellular network) via a wired or
wireless communication link. Some UEs may be considered
Internet-of-Things (IoT) devices, which may be narrowband IoT
(NB-IoT) devices.
[0043] Certain wireless networks (e.g., LTE) utilize orthogonal
frequency division multiplexing (OFDM) on the downlink and
single-carrier frequency division multiplexing (SC-FDM) on the
uplink. OFDM and SC-FDM partition the system bandwidth into
multiple (K) orthogonal subcarriers, which are also commonly
referred to as tones, bins, etc. Each subcarrier may be modulated
with data. In general, modulation symbols are sent in the frequency
domain with OFDM and in the time domain with SC-FDM. The spacing
between adjacent subcarriers may be fixed, and the total number of
subcarriers (K) may be dependent on the system bandwidth. For
example, the spacing of the subcarriers may be 15 kHz and the
minimum resource allocation (called a "resource block" (RB)) may be
12 subcarriers (or 180 kHz). Consequently, the nominal Fast Fourier
Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for
system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz),
respectively. The system bandwidth may also be partitioned into
subbands. For example, a subband may cover 1.08 MHz (i.e., 6
resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for
system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.
[0044] While aspects of the examples described herein may be
associated with LTE technologies, aspects of the present disclosure
may be applicable with other wireless communications systems, such
as NR. NR may utilize OFDM with a CP on the uplink and downlink and
include support for half-duplex operation using TDD. Beamforming
may be supported and beam direction may be dynamically configured.
MIMO transmissions with precoding may also be supported. MIMO
configurations in the DL may support up to 8 transmit antennas with
multi-layer DL transmissions up to 8 streams and up to 2 streams
per UE. Multi-layer transmissions with up to 2 streams per UE may
be supported. Aggregation of multiple cells may be supported with
up to 8 serving cells.
[0045] In some examples, access to the air interface may be
scheduled. A scheduling entity (e.g., a BS) allocates resources for
communication among some or all devices and equipment within its
service area or cell. The scheduling entity may be responsible for
scheduling, assigning, reconfiguring, and releasing resources for
one or more subordinate entities. That is, for scheduled
communication, subordinate entities utilize resources allocated by
the scheduling entity. Base stations are not the only entities that
may function as a scheduling entity. In some examples, a UE may
function as a scheduling entity and may schedule resources for one
or more subordinate entities (e.g., one or more other UEs), and the
other UEs may utilize the resources scheduled by the UE for
wireless communication. In some examples, a UE may function as a
scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh
network. In a mesh network example, UEs may communicate directly
with one another in addition to communicating with a scheduling
entity.
[0046] In FIG. 1, a solid line with double arrows indicates desired
transmissions between a UE and a serving BS, which is a BS
designated to serve the UE on the downlink and/or uplink. A finely
dashed line with double arrows indicates interfering transmissions
between a UE and a BS.
[0047] FIG. 2 illustrates an example logical architecture of a
distributed Radio Access Network (RAN) 200, which may be
implemented in the wireless communication network 100 illustrated
in FIG. 1. A 5G access node 206 may include an access node
controller (ANC) 202. ANC 202 may be a central unit (CU) of the
distributed RAN 200. The backhaul interface to the Next Generation
Core Network (NG-CN) 204 may terminate at ANC 202. The backhaul
interface to neighboring next generation access Nodes (NG-ANs) 210
may terminate at ANC 202. ANC 202 may include one or more TRPs 208
(e.g., cells, BSs, gNBs, etc.).
[0048] The TRPs 208 may be a distributed unit (DU). TRPs 208 may be
connected to a single ANC (e.g., ANC 202) or more than one ANC (not
illustrated). For example, for RAN sharing, radio as a service
(RaaS), and service specific AND deployments, TRPs 208 may be
connected to more than one ANC. TRPs 208 may each include one or
more antenna ports. TRPs 208 may be configured to individually
(e.g., dynamic selection) or jointly (e.g., joint transmission)
serve traffic to a UE.
[0049] The logical architecture of distributed RAN 200 may support
fronthauling solutions across different deployment types. For
example, the logical architecture may be based on transmit network
capabilities (e.g., bandwidth, latency, and/or jitter).
[0050] The logical architecture of distributed RAN 200 may share
features and/or components with LTE. For example, next generation
access node (NG-AN) 210 may support dual connectivity with NR and
may share a common fronthaul for LTE and NR.
[0051] The logical architecture of distributed RAN 200 may enable
cooperation between and among TRPs 208, for example, within a TRP
and/or across TRPs via ANC 202. An inter-TRP interface may not be
used.
[0052] Logical functions may be dynamically distributed in the
logical architecture of distributed RAN 200. As will be described
in more detail with reference to FIG. 5, the Radio Resource Control
(RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio
Link Control (RLC) layer, Medium Access Control (MAC) layer, and a
Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP
208) or CU (e.g., ANC 202).
[0053] FIG. 3 illustrates an example physical architecture of a
distributed RAN 300, according to aspects of the present
disclosure. A centralized core network unit (C-CU) 302 may host
core network functions. C-CU 302 may be centrally deployed. C-CU
302 functionality may be offloaded (e.g., to advanced wireless
services (AWS)), in an effort to handle peak capacity.
[0054] A centralized RAN unit (C-RU) 304 may host one or more ANC
functions. Optionally, the C-RU 304 may host core network functions
locally. The C-RU 304 may have distributed deployment. The C-RU 304
may be close to the network edge.
[0055] A DU 306 may host one or more TRPs (Edge Node (EN), an Edge
Unit (EU), a Radio Head (RH), a Smart Radio Head (SRH), or the
like). The DU may be located at edges of the network with radio
frequency (RF) functionality.
[0056] FIG. 4 illustrates example components of BS 110 and UE 120
(as depicted in FIG. 1), which may be used to implement aspects of
the present disclosure. For example, antennas 452, processors 466,
458, 464, and/or controller/processor 480 of the UE 120 and/or
antennas 434, processors 420, 430, 438, and/or controller/processor
440 of the BS 110 may be used to perform the various techniques and
methods described herein and illustrated with reference to FIG. 9.
For example, as shown in FIG. 4, the controller/processor 480 has a
TA command determination module configured to interpret the TA
command, in accordance with certain aspects of the present
disclosure.
[0057] At the BS 110, a transmit processor 420 may receive data
from a data source 412 and control information from a
controller/processor 440. The control information may be for the
physical broadcast channel (PBCH), physical control format
indicator channel (PCFICH), physical hybrid ARQ indicator channel
(PHICH), physical downlink control channel (PDCCH), group common
PDCCH (GC PDCCH), etc. The data may be for the physical downlink
shared channel (PDSCH), etc. The processor 420 may process (e.g.,
encode and symbol map) the data and control information to obtain
data symbols and control symbols, respectively. The processor 420
may also generate reference symbols, e.g., for the primary
synchronization signal (PSS), secondary synchronization signal
(SSS), and cell-specific reference signal (CRS). A transmit (TX)
multiple-input multiple-output (MIMO) processor 430 may perform
spatial processing (e.g., precoding) on the data symbols, the
control symbols, and/or the reference symbols, if applicable, and
may provide output symbol streams to the modulators (MODs) 432a
through 432t. Each modulator 432 may process a respective output
symbol stream (e.g., for OFDM, etc.) to obtain an output sample
stream. Each modulator may further process (e.g., convert to
analog, amplify, filter, and upconvert) the output sample stream to
obtain a downlink signal. Downlink signals from modulators 432a
through 432t may be transmitted via the antennas 434a through 434t,
respectively.
[0058] At the UE 120, the antennas 452a through 452r may receive
the downlink signals from the base station 110 and may provide
received signals to the demodulators (DEMODs) in transceivers 454a
through 454r, respectively. Each demodulator 454 may condition
(e.g., filter, amplify, downconvert, and digitize) a respective
received signal to obtain input samples. Each demodulator may
further process the input samples (e.g., for OFDM, etc.) to obtain
received symbols. A MIMO detector 456 may obtain received symbols
from all the demodulators 454a through 454r, perform MIMO detection
on the received symbols if applicable, and provide detected
symbols. A receive processor 458 may process (e.g., demodulate,
deinterleave, and decode) the detected symbols, provide decoded
data for the UE 120 to a data sink 460, and provide decoded control
information to a controller/processor 480.
[0059] On the uplink, at UE 120, a transmit processor 464 may
receive and process data (e.g., for the physical uplink shared
channel (PUSCH)) from a data source 462 and control information
(e.g., for the physical uplink control channel (PUCCH) from the
controller/processor 480. The transmit processor 464 may also
generate reference symbols for a reference signal (e.g., for the
sounding reference signal (SRS)). The symbols from the transmit
processor 464 may be precoded by a TX MIMO processor 466 if
applicable, further processed by the demodulators in transceivers
454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the
base station 110. At the BS 110, the uplink signals from the UE 120
may be received by the antennas 434, processed by the modulators
432, detected by a MIMO detector 436 if applicable, and further
processed by a receive processor 438 to obtain decoded data and
control information sent by the UE 120. The receive processor 438
may provide the decoded data to a data sink 439 and the decoded
control information to the controller/processor 440.
[0060] The controllers/processors 440 and 480 may direct the
operation at the BS 110 and the UE 120, respectively. The processor
440 and/or other processors and modules at the BS 110 may perform
or direct the execution of processes for the techniques described
herein. The memories 442 and 482 may store data and program codes
for BS 110 and UE 120, respectively. A scheduler 444 may schedule
UEs for data transmission on the downlink and/or uplink.
[0061] FIG. 5 illustrates a diagram 500 showing examples for
implementing a communications protocol stack, according to aspects
of the present disclosure. The illustrated communications protocol
stacks may be implemented by devices operating in a wireless
communication system, such as a 5G system (e.g., a system that
supports uplink-based mobility). Diagram 500 illustrates a
communications protocol stack including a RRC layer 510, a PDCP
layer 515, a RLC layer 520, a MAC layer 525, and a PHY layer 530.
In various examples, the layers of a protocol stack may be
implemented as separate modules of software, portions of a
processor or ASIC, portions of non-collocated devices connected by
a communications link, or various combinations thereof. Collocated
and non-collocated implementations may be used, for example, in a
protocol stack for a network access device (e.g., ANs, CUs, and/or
DUs) or a UE.
[0062] A first option 505-a shows a split implementation of a
protocol stack, in which implementation of the protocol stack is
split between a centralized network access device (e.g., an ANC 202
in FIG. 2) and distributed network access device (e.g., DU 208 in
FIG. 2). In the first option 505-a, an RRC layer 510 and a PDCP
layer 515 may be implemented by the central unit, and an RLC layer
520, a MAC layer 525, and a PHY layer 530 may be implemented by the
DU. In various examples the CU and the DU may be collocated or
non-collocated. The first option 505-a may be useful in a macro
cell, micro cell, or pico cell deployment.
[0063] A second option 505-b shows a unified implementation of a
protocol stack, in which the protocol stack is implemented in a
single network access device. In the second option, RRC layer 510,
PDCP layer 515, RLC layer 520, MAC layer 525, and PHY layer 530 may
each be implemented by the AN. The second option 505-b may be
useful in, for example, a femto cell deployment.
[0064] Regardless of whether a network access device implements
part or all of a protocol stack, a UE may implement an entire
protocol stack as shown in 505-c (e.g., the RRC layer 510, the PDCP
layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer
530).
[0065] In LTE, the basic transmission time interval (TTI) or packet
duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but
the basic TTI is referred to as a slot. A subframe contains a
variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots)
depending on the subcarrier spacing. The NR RB is 12 consecutive
frequency subcarriers. NR may support a base subcarrier spacing of
15 KHz and other subcarrier spacing may be defined with respect to
the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz,
240 kHz, etc. The symbol and slot lengths scale with the subcarrier
spacing. The CP length also depends on the subcarrier spacing.
[0066] FIG. 6 is a diagram showing an example of a frame format 600
for NR. The transmission timeline for each of the downlink and
uplink may be partitioned into units of radio frames. Each radio
frame may have a predetermined duration (e.g., 10 ms) and may be
partitioned into 10 subframes, each of 1 ms, with indices of 0
through 9. Each subframe may include a variable number of slots
depending on the subcarrier spacing. Each slot may include a
variable number of symbol periods (e.g., 7 or 14 symbols) depending
on the subcarrier spacing. The symbol periods in each slot may be
assigned indices. A mini-slot, which may be referred to as a
sub-slot structure, refers to a transmit time interval having a
duration less than a slot (e.g., 2, 3, or 4 symbols).
[0067] Each symbol in a slot may indicate a link direction (e.g.,
DL, UL, or flexible) for data transmission and the link direction
for each subframe may be dynamically switched. The link directions
may be based on the slot format. Each slot may include DL/UL data
as well as DL/UL control information.
[0068] In NR, a synchronization signal (SS) block is transmitted.
The SS block includes a PSS, a SSS, and a two symbol PBCH. The SS
block can be transmitted in a fixed slot location, such as the
symbols 0-3 as shown in FIG. 6. The PSS and SSS may be used by UEs
for cell search and acquisition. The PSS may provide half-frame
timing, the SS may provide the CP length and frame timing. The PSS
and SSS may provide the cell identity. The PBCH carries some basic
system information, such as downlink system bandwidth, timing
information within radio frame, SS burst set periodicity, system
frame number, etc. The SS blocks may be organized into SS bursts to
support beam sweeping. Further system information such as,
remaining minimum system information (RMSI), system information
blocks (SIBs), other system information (OSI) can be transmitted on
a physical downlink shared channel (PDSCH) in certain subframes.
The SS block can be transmitted up to sixty-four times, for
example, with up to sixty-four different beam directions for mmW.
The up to sixty-four transmissions of the SS block are referred to
as the SS burst set. SS blocks in an SS burst set are transmitted
in the same frequency region, while SS blocks in different SS
bursts sets can be transmitted at different frequency
locations.
[0069] In some circumstances, two or more subordinate entities
(e.g., UEs) may communicate with each other using sidelink signals.
Real-world applications of such sidelink communications may include
public safety, proximity services, UE-to-network relaying,
vehicle-to-vehicle (V2V) communications, Internet of Everything
(IoE) communications, IoT communications, mission-critical mesh,
and/or various other suitable applications. Generally, a sidelink
signal may refer to a signal communicated from one subordinate
entity (e.g., UE1) to another subordinate entity (e.g., UE2)
without relaying that communication through the scheduling entity
(e.g., UE or BS), even though the scheduling entity may be utilized
for scheduling and/or control purposes. In some examples, the
sidelink signals may be communicated using a licensed spectrum
(unlike wireless local area networks, which typically use an
unlicensed spectrum).
Example Supplemental Uplink
[0070] Certain wireless communication system deployments utilize
multiple downlink (DL) component carriers (CCs) as part of a
carrier aggregation (CA) scheme. For example, in addition to a
primary DL CC, one or more supplemental DL (SDL) CCs may be used to
enhance date throughput and/or reliability.
[0071] As illustrated in FIG. 7, for certain systems (e.g., such as
5G NR), one or more supplemental UL (SUL) CCs may also be utilized.
A SUL may generally refer to an UL CC without a corresponding DL CC
(e.g., no paired DL) in the cell. In other words, SUL may generally
refer to the case when there is only UL resource for a carrier from
the perspective of an NR device. As shown in FIG. 7, SUL may allow
for a scenario where there is a one DL CC and multiple UL CCs in a
cell. In some cases, there may be a one-to-multiple relationship
between DL and UL. When cells are co-located, the SUL and primary
UL (PUL) may belong to the same timing advance group (TAG).
[0072] In NR, UE specific RRC signaling may (re)-configure the
location of PUCCH either on the SUL carrier or on a non-SUL UL
carrier in a SUL band combination. The default location of the
PUSCH may be the same carrier that is used by PUCCH. Further, UE
specific RRC signaling may (de)-configure that PUSCH be dynamically
scheduled on the other (i.e., non-PUCCH) carrier in the same cell
as the SUL. In this case, a carrier indicator field (CIF) in the UL
grant may be used to indicate (e.g., dynamically) whether the PUSCH
is transmitted on the PUCCH carrier or on the other carrier. There
may be one active bandwidth part (BWP) on the SUL carrier and one
active BWP on the non-SUL UL carrier.
[0073] SRS related RRC parameters may be independently configured
for SRS on the SUL carrier and SRS on the non-SUL UL carrier in the
SUL band combination. For example, SRS can be configured on the SUL
carrier and non-SUL UL carrier, regardless of the carrier
configuration for PUSCH and PUCCH.
Example TA Granularity for UL with Different Numerologies
[0074] For uplink transmission, a timing advance (TA) is generally
used to ensure that signals from different UEs arrive at the base
station (e.g., a gNB) synchronously (e.g., are orthogonal) to avoid
performance loss. Typically, the amount of the TA, also referred to
as the TA command, is signaled from the gNB to the UE. For example,
the gNB may signal the TA in a medium access control (MAC) control
element (CE) of the random access response (RAR) during a random
access procedure. After receiving the RAR, the UE may send a first
uplink transmission based on the TA. For example, the UE applies a
timing adjustment to the uplink transmission based on the TA.
[0075] In NR, the TA granularity (e.g., the units of the TA
command) is generally based on one or more parameters associated
with the numerology of the uplink carrier. As used herein, the term
numerology generally refers to a set of parameters that define a
structure of time and frequency resources used for communication.
Such parameters may include, for example, subcarrier spacing (SCS),
type of cyclic prefix (e.g., such as normal CP or extended CP), and
transmission time intervals (TTIs) (e.g., such as subframe or slot
durations).
[0076] In one reference example shown in the Table 800 in FIG. 8,
the TA granularity (TA unit) is based on the subcarrier spacing of
the first uplink transmission after RAR. As shown, the unit of the
TA (e.g., the TA granularity) scales with the subcarrier spacing
(e.g., an aspect of the numerology) for the single numerology case
(e.g., in the case where one or more uplink carriers have the same
numerology).
[0077] In some cases, NR may support mixed numerologies across
cells with carrier aggregation and/or across BWP(s) within a cell.
In some examples, a PUL and SUL, which may belong to the same TAG,
may have different numerologies. In some examples, one or more UL
BWPs of the carrier(s) within the cell can have different
numerologies. In scenarios where the uplink within the cell has a
mixed numerology, the gNB (using conventional techniques) may not
be able to accurately determine the TA granularity to use for TA
command(s).
[0078] According to certain aspects, the gNB may determine a TA
configuration (e.g., TA granularity) for a TA command among uplink
carriers associated with mixed (different) UL numerologies. The BS
to share the same TA command across uplink carriers (e.g., PUL and
SUL) with different numerologies.
[0079] In some aspects, the BS may determine the TA configuration
to use for the TA command, based on the TA granularity used for
each of the uplink carriers. Assuming PUL and SUL are the uplink
carriers, the BS may determine a TA granularity of the PUL CC
(e.g., based on the numerology used for PUL CC), and determine a TA
granularity of the SUL CC (e.g., based on the numerology used for
PUL CC). The BS may determine the TA granularity of the TA command
based on the determined TA granularity of both the PUL CC and SUL
CC. For example, in one aspect, the BS may determine the TA
granularity to use for the TA command based on a maximum or minimum
of the TA granularity of SUL TA and TA granularity of PUL TA.
[0080] In some aspects, the BS may determine the TA granularity of
the TA command based on the numerology of the PUCCH carrier. For
example, the base station may determine which of the uplink
carriers is associated with a PUCCH, and determine the TA
granularity of the TA command based on the TA granularity of the
determined uplink carrier associated with PUCCH.
[0081] In some aspects, the BS may determine one of the uplink
carriers that is associated with a particular carrier index (e.g.,
index zero, or the minimum or the maximum among all the uplink
carrier indices, or a specific index indicated by RRC
configuration), and determine the TA granularity of the TA command
based on the TA granularity of the determined uplink carrier. The
index of each carrier itself may be configured or reconfigured, for
example, by RRC signaling, and this may provide a method of
changing the TA granularity when needed.
[0082] In some aspects, the BS may determine the TA granularity
based on a "reference" carrier explicitly configured by the
network. For example, the base station may receive an indication of
one of the uplink carriers to use for the TA granularity of the TA
command, and determine the TA granularity of the TA command based
on the TA granularity of the indicated uplink carrier.
[0083] As noted above, NR may also support different numerologies
across different portions of bandwidth (or BWPs within one or more
carriers of the cell. That is, a cell encompassing UL may be
configured with multiple UL BWPs with different numerologies. The
BWP may be defined by a particular frequency range, center
frequency, and/or numerology. Although the CC can include multiple
BWP configurations, in general there is a single BWP that is active
at any given time. However, the active UL BWP may dynamically
change (e.g., based on DCI).
[0084] Thus, if TA granularity is based on the numerology of the
current active UL BWP, then the TA granularity would also have to
dynamically change any time the current active UL BWP changes.
However, because the BWP switch command (used to switch the active
UL BWP) is based on DCI and the TA command is based on MAC CE, the
base station may have to align the timing of the BWP switch command
and MAC CE command in order to ensure that the correct TA
granularity is used for the current active UL BWP.
[0085] According to certain aspects, the BS may achieve timing
alignment between the TA command (e.g., based on MAC-CE) and BWP
switching command (e.g., based on DCI).
[0086] In an illustrative example, a BWP1 and a BWP2 (for a single
carrier) have different numerologies. When the MAC-CE command is
decoded (e.g., by a UE), the TA granularity is dependent on the BWP
which is active at that time instance. However, a timing ambiguity
can result at this time instance. For example, even though the
MAC-CE command is sent assuming BWP1's TA granularity, the command
may not have been decoded successfully on the 1.sup.st
transmission, and a HARQ retransmission may be needed. However,
before the retransmission is completed, the active BWP may switch
from BWP1 to BWP2. In this situation, the UE may not know how to
interpret the MAC-CE command's TA granularity (e.g., based on BWP1
or BWP2).
[0087] In some examples, the MAC-CE TA command ACK timing can be
used to determine the BWP numerology to use. To avoid ambiguity,
the gNB may defer BWP switching when MAC-CE with TA command is
pending HARQ retransmission. If the HARQ retransmission completes
and there is still a NACK, this implies that the TA command still
did not get through. Thus, the gNB may determine to restart the
MAC-CE TA command transmission in BWP1 and continue to defer
switching to BWP2. Alternatively, the gNB may determine to restart
the MAC-CE TA command transmission in BWP2 after switching from
BWP1 to BWP2.
[0088] Dynamically changing the TA granularity in this manner may
not be desirable due in part to difficulty in aligning the timing
of the BWP switch command (based on DCI) and TA command (based on
MAC CE).
[0089] According to certain aspects, the BS can reliably determine
the TA granularity for the TA command in situations where the
active BWP is dynamically changing.
[0090] In some examples, the BS may determine, for each of the one
or more uplink carriers, a numerology associated with one or more
configured BWPs of the uplink carrier. There may be multiple
configured BWPs for each carrier, but one active BWP among the
configured BWPs. Using PUL and SUL as a reference example, PUL may
include one or more configured BWPs having different numerologies
and SUL may include one or more configured BWPs having different
numerologies. Once determined, the base station may determine the
TA configuration to use for the TA command further based on the
numerology of each configured BWP.
[0091] In some examples, the BS may determine the TA granularity of
the TA command based on a maximum TA granularity of the BWPs or a
minimum TA granularity of the BWPs. This determination can be done
in a semi-statically manner, since in general the UL BWPs are RRC
configured for the cell. Thus, even if the BWP is dynamically
changing, the BS can use the same determined TA granularity for the
TA command.
[0092] In some aspects, the BS may designate (or select) one of the
UL BWPs as the "reference" UL BWP. For example, in TDD, the
designated UL BWP can be the one associated with the default DL
BWP. In another example, the designated UL BWP can be the one
associated with a particular BWP index (e.g., index zero, or the
minimum or the maximum among all the uplink BWP indices). The BS
may determine the TA granularity of the TA command based on the TA
granularity of the selected bandwidth part (determined from the
reference UL BWP's numerology). The index of each BWP may be
configured or reconfigured, for example, by RRC signaling, such
that the TA granularity can be changed/updated when needed.
Further, the BWPs may be indexed separately within each CC, or may
be jointly indexed across all CCs. If separate indexing is used,
multiple BWPs in different CCs may have the same index, and the
designated UL BWP can then be the one associated with a particular
BWP index within a particular carrier index.
[0093] Accordingly, aspects presented herein can be used to resolve
the issue of the ambiguity with TA granularity in mixed UL
numerology.
Example TA Command Interpretation for TAG with Mixed
Numerologies
[0094] As described above, for uplink transmission, a timing
advance (TA) is used to ensure that signals from different user
equipment (UEs) generally arrive at the base station (BS) in a
synchronous manner (e.g., are orthogonal) to avoid performance
loss. As described above, in certain systems (e.g., such as 5G NR
systems), the TA granularity (e.g., the units of the TA command) is
based on one or more parameters associated with the numerology of
the uplink carrier and, therefore, can be different for different
numerologies. The term numerology refers to a set of parameters
that define a structure of time and frequency resources used for
communication. Such parameters may include, for example, the
subcarrier spacing (SCS), the type of cyclic prefix (e.g., such as
normal CP or extended CP), and/or the transmission time intervals
(TTIs, e.g., such as subframe or slot durations). For example, a
numerology with a larger SCS may be associated with a shorter
symbol duration and a control timing with finer TA granularity
(e.g., ability for finer timing adjustments), and a numerology with
a smaller SCS may be associated with a longer symbol duration and
coarser timing adjustments (e.g., larger timing adjustments as
compared to numerologies having a larger SCS).
[0095] In some examples, a timing adjustment group (TAG) includes
members or components associated with different numerologies (e.g.,
different SCS which may be referred to as tone spacing). Members of
the TAG be associated with bandwidth parts (BWPs) and/or component
carriers (CCs) that do not all share a common SCS. A single TA
command is used for all of the members of the TAG (e.g., all BWPs
and CCs). Unlike systems, such as long term evolution (LTE)
systems, where the SCS is fixed (e.g., at 15 kHz), certain systems,
such as 5G NR systems, support UL transmissions having different
SCS (i.e., mixed numerologies). Thus, the TA command for the TAG
may not ensure synchronous (e.g., orthogonal) reception at the BS
due to the different numerologies associated with the TAG.
[0096] Aspects of the present disclosure provide methods and
apparatus for members of a TAG having different numerologies to
interpret a same TA command. In an example, the command may be
interpreted as a same TA for all members of the TAG. Alternatively,
and as described in more detail herein, the TA may be interpreted
differently based on a numerology associated with the member of the
TAG. For example, the TA command may be interpreted differently
based on a SCS associated with a respective member of the TAG.
[0097] As described above, components or members of a TAG may have
different tone spacing (i.e., different SCS). In some examples, the
TA command granularity (e.g., units of the TA command) for a TAG is
tied to or associated with a specific SCS, referred to as the "TAG
SCS." The TAG SCS may be communicated to UEs (e.g., members of the
TAG). In some examples, the TAG SCS is communicated to the UEs via
RRC signaling. Accordingly, the TA command may indicate the TA
granularity (e.g., units of TA) that is tied to the TAG SCS.
[0098] According to certain aspects, when a TAG is configured, all
CCs and BWPs associated with the TAG and the TAG SCS to be used to
determine the TA granularity may be identified. In some examples,
the TAG SCS is based on the minimum/smallest SCS associated with a
member of the TAG. Thus, the TA granularity for the TAG is tied to
the smallest SCS for members of the TAG. The minimum SCS is
associated with the largest OFDM symbol duration and the coarsest
timing adjustment. Therefore, if the TA command granularity is
associated with the minimum SCS, all members of the group will be
able to apply the same TA command (no fractional TA will be applied
by any member). This is because the minimum SCS is associated with
the coarsest timing adjustment, which is a multiple of the finer
granularity adjustments. In this case, UL transmissions associated
with a larger SCS than the minimum SCS of the TAG are able to
control timing with a finer granularity but may not do so because
they are limited by the coarser granularity indicated in the TA
command.
[0099] Associating the TA command with the minimum SCS for members
of the TAG may be applied in the supplemental UL (SUL) scenario,
where a single DL carrier is assigned to two UL carriers and each
of the UL carriers have different numerologies. Similarly, a TA
command associated with a minimum SCS may be applied to different
CCs within a frequency band, or different BWPs in a system
bandwidth, where the different CCs or BWPs have different
numerologies.
[0100] According to certain aspects, the TA command granularity may
be associated with an SCS other than the minimum SCS of the TAG
(e.g., such as the maximum SCS of the TAG). It may be challenging
to apply the granularity associated with the larger TAG SCS to
members having of the TAG having an SCS that is smaller than the
indicated TAG SCS. For example, application of the TA command for
members of the TAG having an SCS less than the indicated TAG SCS
may require timing adjustments that are a fraction of the natural
TA granularity associated with the member (e.g., a fraction of a CC
or BWP associated with the TAG member). Thus, members of the TAG
associated with SCS smaller than the TAG SCS may natively support
timing adjustments of coarser granularity as compared to the finer
TAG command granularity.
[0101] According to certain aspects, when the TA command
granularity (larger TAG SCS) is finer than the coarse granularity
supported by a member (with a smaller SCS), the UE may round the TA
command granularity to a natural TA granularity supported by the
member. For example, for a CC or BWP of the TAG having a SCS that
is smaller than the TAG SCS, the UE may round the granularity to
the coarsest TA granularity supported by the CC or BWP. In some
examples, the UE applies the rounded TA to all members of the TAG.
This may have the same effect as using the SCS of the CC or BWP
(that is less than the indicated TAG SCS) as the TAG SCS or as
using the minimum SCS of all CC/BWPs in the TAG to define the TA
granularity applicable to all members of the TAG.
[0102] According to other aspects, the TA command may be
interpreted differently for different members of the TAG. In some
examples, for members of the TAG with an SCS that is less than the
TAG SCS, the UE may apply the rounded TA, for example, in an effort
to avoid the applying a fraction of its natural TA granularity
associated with the CC or BWP. Thus, the UE may interpret the TA
command as the rounded TA command for members of the TAG (e.g.,
CCs/BWPs) that have the smaller SCS. The finer granularity
associated with the TA command may be preserved and used/applied by
members of the TAG having a SCS that is equal to or larger than the
TAG SCS. Thus, the same TA command may be interpreted differently
for different members of the TAG having different numerologies and
may avoid any member applying a fractional portion of the member's
natural TA granularity.
[0103] For members of the TAG having an SCS less than the TAG SCS,
additional actions may be taken to help maintain synchronization of
received UL transmissions at the BS. According to certain aspects,
the UE may track a rounding error between the TA command
granularity and the (rounded) TA applied to a member. For example,
instead of simply processing future TA commands, the rounding error
or difference may be applied to future UL transmissions. In some
examples, the UE may recognize that a quantized version of a TA
command was applied to the member, determine the error due to the
quantization, and accumulate the quantization error with a next
command or next UL transmission in an effort to avoid errors from
accumulating. Tracking the difference and applying it to future UL
transmissions helps UL transmissions from the TAG remain
time-aligned. In some examples, the UE may apply the difference to
a next or later-received TA command. In some examples, the UE
autonomously applies the difference based on a determined change in
DL timing at the UE. A change in DL timing at the UE may occur, for
example, when the UE is moving, either further away from the BS or
closer to the BS. Autonomous application refers to the UE applying
the error to subsequent UL transmissions absent receiving an
explicit TA command.
[0104] According to certain aspects, errors or differences may be
included or excluded from computations regulating the UE's DL
timing-based UL adjustments (e.g., limits on per-instantaneous
adjustment and on rate of adjustment over time). A UE may be able
to make a limited number of instantaneous adjustments or a limited
number of adjustments in a given time window. Application of the
accumulation errors may or may not contribute to these limits
[0105] Certain events may reset the tracking of the rounding errors
(differences). In some examples, based on triggering events, the
accumulated rounded error may be reset. In some examples, because
the difference between the TA command granularity and the applied
TA was based on a SCS, a reconfiguration of BWPs and/or CCs or a
change in SCS may trigger resetting the accumulation of
differences. In some examples, a change in the TAG SCS may trigger
resetting the errors. In some examples, an explicit reset command
transmitted via RRC signaling or a MAC-CE may force a reset of
errors. Expiry of a TA-timer may indicate link failure. In some
examples, the UE may begin a RACH procedure or make limited
transmissions upon expiry of the TA-timer, and the UE may reset the
error when the TA-timer expires.
[0106] According to certain aspects, the options described herein
for interpreting a TA command may depend on the UE's capability and
RRC configuration.
[0107] FIG. 9 illustrates example operations 900 that may be
performed by a UE, in accordance with aspects of the present
disclosure. The UE may include one or more components illustrated
in FIG. 4. Operations 900 may be implemented as software components
that are executed and run on one or more processors (e.g.,
processor 480 of FIG. 4). Further, the transmission and reception
of signals by the UE in operations 900 may be enabled, for example,
by one or more antennas (e.g., antennas 452 of FIG. 4). In certain
aspects, the transmission and/or reception of signals by the UE may
be implemented via a bus interface of one or more processors (e.g.,
processor 480) obtaining and/or outputting signals.
[0108] At 905, the UE may receive, from a BS, a TA command. As
described above, a TA granularity of a TA command is associated
with an SCS. The TA granularity is defined by any combination of
predetermined rules (e.g., agreed upon in a standard) and/or RRC
signaling. As an example, the granularity may be hardwired into the
UE (e.g., defined in a technical standard supported by the UE). The
formula may be based on a function of the numerology, such as the
SCS.
[0109] At 910, the UE may interpret the TA command differently for
different members of a same TAG, wherein the members of the TAG are
associated with different numerologies. In some examples, the
numerologies may be associated with different SCS. Based on the SCS
of a member and a received TAG SCS, the UE may round the TA
granularity in a received TA command. The UE may compare the SCS of
the member to the SCS associated with the TA granularity (e.g., the
TAG SCS). Based on the comparison, the UE may interpret the TA
command. Members of the TAG may include one or more CCs and/or one
or more BWPs.
[0110] At 906, the UE may apply a timing adjustment when
transmitting an uplink transmission to the BS based, at least in
part, on the interpretation. In some examples, the UE may apply the
determined timing adjustment to the member, or apply the TA
granularity as indicated in the command.
[0111] The UE may apply the timing adjustment by applying the TA
command differently based on the SCS associated with a respective
member of the TAG. For example, when the SCS is less than an
indicated SCS of the TA granularity, the UE may apply the rounded
granularity of the TA command. The rounded granularity may be a
nominal coarse TA that is larger than the TA associated with the TA
command. In another example, when the SCS of a member of the TAG is
not an integer multiple of the indicated SCS of the TA granularity,
the UE may apply the rounded granularity of the TA command.
[0112] On the other hand, when an SCS of a member of the TAG is
greater than or equal to the indicated SCS of the TA granularity UE
may apply the TA granularity indicated in the TA command (e.g., no
rounding). In another example, when the SCS of a member of the TAG
is an integer multiple of the indicated SCS of the TA granularity,
the UE may apply the TA granularity indicated in the TA command
without rounding.
[0113] When the UE applies a rounded TA granularity, the UE may
track differences between the TA granularity associated with the
indicated subcarrier SCS and the nominal coarse TA granularity
applied. The difference may be applied to subsequent TA commands.
The difference may be applied autonomously by the UE. Accumulated
differences may be reset, for example, upon reconfiguration of
members of the TAG, a change in the indicated SCS, a received
command from the BS, and/or upon expiry of a TA-timer.
[0114] As described herein, components (e.g., members) of a TAG may
be associated with different numerologies. To maintain
synchronization of received signals at a BS, members of a TAG may
apply different interpretations of a TA command. The interpretation
may be based, at least in part, on a numerology associated with
each member and a TAG SCS which is associated with a TA granularity
for the TAG.
[0115] The example described above discuss, for simplicity, that
rounding of the TA commands is done for CCs and/or BWPs with SCS
smaller than the TAG SCS, and is not done otherwise. However, the
concepts described above are not limited by these examples, and are
readily extended to other examples of when rounding is, or is not,
done. For example, the UE may apply the TA command without
rounding, and/or accumulation of rounding errors, even to certain
CCs and/or BWPs with SCS less than TAG SCS. In some examples, the
set of CCs and/or BWPs for which the UE is able to directly apply
the TA command may be communicated with the BS, for example, as
part of UE capability signaling, and the UE may be allowed to apply
the TA command without rounding for CCs or BWPs within that set. In
some examples, for SCS that is not a multiple of all the smaller
allowed SCS (i.e., the ratio of any two SCS is not necessarily a
power of 2), rounding may be done even for BWPs and/or CCs whose
SCS is equal or greater than the TAG SCS (e.g., the SCS is not a
multiple of the TAG SCS).
[0116] According to certain aspects, rounding may include rounding
the TA command down (e.g., flooring), rounding the TA command up
(e.g., ceiling), or rounding the TA command to the nearest
supported granularity. The TA may be rounded such that the rounded
TA may is an integer multiple of the TA granularity associated with
the SCS of a member of the TAG.
[0117] In some examples, the TA command prior to rounding may be
equally close to the nearest supported granularities obtained by
rounding down or rounding up. The UE may round down, round up, or
be configured regarding how to round received TA commands (TA
granularity). The UE may randomly determine, for each TA command,
whether it will round up or round down the TA granularity. The UE
may select, via a deterministic pattern across a number of received
TA commands, for example, a number of successively received TA
commands, whether it will round up or round down. For example, the
UE may alternate between rounding up or rounding down the
granularity to be applied.
[0118] The choice between the various possible rounding behaviors
described above may also be a function of whether or not the UE
accumulates its rounding errors, and/or the UE capability.
[0119] According to certain aspects, a BS may perform operations
complementary to the operations 900 that may be performed by the
UE.
[0120] FIG. 10 illustrates a communications device 1000 that may
include various components (e.g., corresponding to
means-plus-function components) configured to perform operations
for the techniques disclosed herein, such as the operations
illustrated in FIG. 9. The communications device 1000 includes a
processing system 1002 coupled to a transceiver 1008. The
transceiver 1008 is configured to transmit and receive signals for
the communications device 1000 via an antenna 1010, such as the
various signals as described herein. The processing system 1002 may
be configured to perform processing functions for the
communications device 1000, including processing signals received
and/or to be transmitted by the communications device 1000.
[0121] The processing system 1002 includes a processor 1004 coupled
to a computer-readable medium/memory 1012 via a bus 1006. In
certain aspects, the computer-readable medium/memory 1012 is
configured to store instructions (e.g., computer-executable code)
that when executed by the processor 1004, cause the processor 1004
to perform the operations illustrated in FIG. 9, or other
operations for performing the various techniques discussed herein
for TA adjustment for mixed numerologies. In certain aspects,
computer-readable medium/memory 1012 stores code 1014 for receiving
a TA command; code 1016 for interpreting the TA command based on
numerology; and code 1018 for applying a timing adjustment for an
uplink transmission based on the interpreted TA command. In certain
aspects, the processor 1004 has circuitry configured to implement
the code stored in the computer-readable medium/memory 1012. The
processor 1004 includes circuitry 1020 for receiving a TA command;
circuitry 1022 for interpreting the TA command based on numerology;
and circuitry 1024 for applying a timing adjustment for an uplink
transmission based on the interpreted TA command.
[0122] The methods disclosed herein comprise one or more steps or
actions for achieving the methods. The method steps and/or actions
may be interchanged with one another without departing from the
scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0123] As used herein, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any
combination with multiples of the same element (e.g., a-a, a-a-a,
a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or
any other ordering of a, b, and c).
[0124] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
looking up (e.g., looking up in a table, a database or another data
structure), ascertaining and the like. Also, "determining" may
include receiving (e.g., receiving information), accessing (e.g.,
accessing data in a memory) and the like. Also, "determining" may
include resolving, selecting, choosing, establishing and the
like.
[0125] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language of the
claims, wherein reference to an element in the singular is not
intended to mean "one and only one" unless specifically so stated,
but rather "one or more." Unless specifically stated otherwise, the
term "some" refers to one or more. All structural and functional
equivalents to the elements of the various aspects described
throughout this disclosure that are known or later come to be known
to those of ordinary skill in the art are expressly incorporated
herein by reference and are intended to be encompassed by the
claims. Moreover, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. No claim element is to be
construed under the provisions of 35 U.S.C. .sctn. 112(f) unless
the element is expressly recited using the phrase "means for" or,
in the case of a method claim, the element is recited using the
phrase "step for."
[0126] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrated circuit
(ASIC), or processor. Generally, where there are operations
illustrated in figures, those operations may have corresponding
counterpart means-plus-function components with similar
numbering.
[0127] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device (PLD), discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any commercially available processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0128] If implemented in hardware, an example hardware
configuration may comprise a processing system in a wireless node.
The processing system may be implemented with a bus architecture.
The bus may include any number of interconnecting buses and bridges
depending on the specific application of the processing system and
the overall design constraints. The bus may link together various
circuits including a processor, machine-readable media, and a bus
interface. The bus interface may be used to connect a network
adapter, among other things, to the processing system via the bus.
The network adapter may be used to implement the signal processing
functions of the PHY layer. In the case of a user terminal 120 (see
FIG. 1), a user interface (e.g., keypad, display, mouse, joystick,
etc.) may also be connected to the bus. The bus may also link
various other circuits such as timing sources, peripherals, voltage
regulators, power management circuits, and the like, which are well
known in the art, and therefore, will not be described any further.
The processor may be implemented with one or more general-purpose
and/or special-purpose processors. Examples include
microprocessors, microcontrollers, DSP processors, and other
circuitry that can execute software. Those skilled in the art will
recognize how best to implement the described functionality for the
processing system depending on the particular application and the
overall design constraints imposed on the overall system.
[0129] If implemented in software, the functions may be stored or
transmitted over as one or more instructions or code on a computer
readable medium. Software shall be construed broadly to mean
instructions, data, or any combination thereof, whether referred to
as software, firmware, middleware, microcode, hardware description
language, or otherwise. Computer-readable media include both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. The processor may be responsible for managing the bus and
general processing, including the execution of software modules
stored on the machine-readable storage media. A computer-readable
storage medium may be coupled to a processor such that the
processor can read information from, and write information to, the
storage medium. In the alternative, the storage medium may be
integral to the processor. By way of example, the machine-readable
media may include a transmission line, a carrier wave modulated by
data, and/or a computer readable storage medium with instructions
stored thereon separate from the wireless node, all of which may be
accessed by the processor through the bus interface. Alternatively,
or in addition, the machine-readable media, or any portion thereof,
may be integrated into the processor, such as the case may be with
cache and/or general register files. Examples of machine-readable
storage media may include, by way of example, RAM (Random Access
Memory), flash memory, ROM (Read Only Memory), PROM (Programmable
Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory),
EEPROM (Electrically Erasable Programmable Read-Only Memory),
registers, magnetic disks, optical disks, hard drives, or any other
suitable storage medium, or any combination thereof. The
machine-readable media may be embodied in a computer-program
product.
[0130] A software module may comprise a single instruction, or many
instructions, and may be distributed over several different code
segments, among different programs, and across multiple storage
media. The computer-readable media may comprise a number of
software modules. The software modules include instructions that,
when executed by an apparatus such as a processor, cause the
processing system to perform various functions. The software
modules may include a transmission module and a receiving module.
Each software module may reside in a single storage device or be
distributed across multiple storage devices. By way of example, a
software module may be loaded into RAM from a hard drive when a
triggering event occurs. During execution of the software module,
the processor may load some of the instructions into cache to
increase access speed. One or more cache lines may then be loaded
into a general register file for execution by the processor. When
referring to the functionality of a software module below, it will
be understood that such functionality is implemented by the
processor when executing instructions from that software
module.
[0131] Also, any connection is properly termed a computer-readable
medium. For example, if the software is transmitted from a website,
server, or other remote source using a coaxial cable, fiber optic
cable, twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared (IR), radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, include
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk, and Blu-ray.RTM. disc where disks usually
reproduce data magnetically, while discs reproduce data optically
with lasers. Thus, in some aspects computer-readable media may
comprise non-transitory computer-readable media (e.g., tangible
media). In addition, for other aspects computer-readable media may
comprise transitory computer-readable media (e.g., a signal).
Combinations of the above should also be included within the scope
of computer-readable media.
[0132] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a
computer-readable medium having instructions stored (and/or
encoded) thereon, the instructions being executable by one or more
processors to perform the operations described herein. For example,
instructions for performing the operations described herein and
illustrated in FIG. 9.
[0133] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein can be downloaded and/or otherwise obtained by a
user terminal and/or base station as applicable. For example, such
a device can be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via storage means
(e.g., RAM, ROM, a physical storage medium such as a compact disc
(CD) or floppy disk, etc.), such that a user terminal and/or base
station can obtain the various methods upon coupling or providing
the storage means to the device. Moreover, any other suitable
technique for providing the methods and techniques described herein
to a device can be utilized.
[0134] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
* * * * *